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Commit f1feda70 authored by Francisco Jerez's avatar Francisco Jerez Committed by Ben Skeggs
Browse files

drm/nouveau: Put back the old 2-messages I2C slave test. 



I was hoping we could detect I2C devices at a given address without
actually writing data into them, but apparently some DDC slaves get
confused with 0-bytes transactions. Put the good old test back.

Reported-by: default avatarBen Skeggs <bskeggs@redhat.com>
Signed-off-by: default avatarFrancisco Jerez <currojerez@riseup.net>
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent e04d8e82

drivers/gpu/drm/nouveau/nouveau_i2c.c

+15 −4
Original line number Diff line number Diff line
@@ -281,12 +281,23 @@ nouveau_i2c_find(struct drm_device *dev, int index) 
bool

nouveau_probe_i2c_addr(struct nouveau_i2c_chan *i2c, int addr)

{

	struct i2c_msg msg = {

	uint8_t buf[] = { 0 };

	struct i2c_msg msgs[] = {

		{

			.addr = addr,

			.flags = 0,

			.len = 1,

			.buf = buf,

		},

		{

			.addr = addr,

		.len = 0,

			.flags = I2C_M_RD,

			.len = 1,

			.buf = buf,

		}

	};



	return i2c_transfer(&i2c->adapter, &msg, 1) == 1;

	return i2c_transfer(&i2c->adapter, msgs, 2) == 2;

}



int